/* 开始界面样式 */
#start-screen {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    overflow: hidden;
}

#start-screen::before {
    content: '';
    position: absolute;
    top: -50px;
    left: -50px;
    right: -50px;
    bottom: -50px;
    background: linear-gradient(45deg, #2c3e50 25%, #34495e 25%, #34495e 50%, #2c3e50 50%, #2c3e50 75%, #34495e 75%);
    background-size: 20px 20px;
    opacity: 0.05;
    z-index: -1;
    animation: slide 20s linear infinite;
}

@keyframes slide {
    0% { transform: translateX(0) translateY(0); }
    100% { transform: translateX(-200px) translateY(-200px); }
}

.game-title-container {
    margin-bottom: 30px;
    position: relative;
}

.game-title-container h1 {
    position: relative;
    display: inline-block;
}

.game-title-container h1::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80%;
    height: 3px;
    background: linear-gradient(90deg, transparent, #3498db, transparent);
}

.game-description {
    font-size: 1.2rem;
    color: #bdc3c7;
    max-width: 600px;
    margin: 0 auto 30px;
}

.difficulty-selection {
    margin: 40px 0;
    padding: 20px;
    background-color: rgba(0, 0, 0, 0.2);
    border-radius: 15px;
    border: 1px solid rgba(52, 152, 219, 0.3);
}

.difficulty-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 20px;
}

.difficulty-btn {
    background-color: rgba(236, 240, 241, 0.1);
    color: #dfe6e9;
    font-size: 1.1rem;
    padding: 12px 30px;
    border: 2px solid rgba(189, 195, 199, 0.3);
    border-radius: 50px;
    transition: all 0.3s ease;
    min-width: 120px;
}

.difficulty-btn:hover {
    background-color: rgba(236, 240, 241, 0.2);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.difficulty-btn.selected {
    background-color: #3498db;
    color: white;
    border-color: #2980b9;
    box-shadow: 0 5px 15px rgba(52, 152, 219, 0.4);
}

.instructions {
    max-width: 650px;
    margin: 40px auto;
    text-align: left;
    background-color: rgba(0, 0, 0, 0.2);
    padding: 25px;
    border-radius: 15px;
    border-left: 4px solid #3498db;
    position: relative;
}

.instructions::before {
    content: '📝';
    position: absolute;
    top: -15px;
    left: 20px;
    background-color: #3498db;
    padding: 5px 10px;
    border-radius: 5px;
    font-size: 1.2rem;
}

.instructions h3 {
    margin-top: 0;
    color: #3498db;
}

.speed-levels {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    margin: 20px 0;
}

.speed-level {
    flex-basis: 48%;
    margin-bottom: 15px;
    padding: 10px;
    background-color: rgba(0, 0, 0, 0.2);
    border-radius: 8px;
    display: flex;
    align-items: center;
}

.speed-icon {
    font-size: 1.5rem;
    margin-right: 10px;
}

.speed-info {
    text-align: left;
}

.speed-name {
    font-weight: bold;
    color: #3498db;
}

.speed-value {
    font-size: 0.9rem;
    color: #bdc3c7;
}

.warning-text {
    color: #e74c3c;
    font-weight: bold;
    margin-top: 15px;
}

/* 结束界面样式 */
#end-screen {
    max-width: 600px;
    margin: 0 auto;
    position: relative;
    overflow: hidden;
}

#end-screen::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #2c3e50 25%, transparent 25%) -10px 0,
                linear-gradient(225deg, #2c3e50 25%, transparent 25%) -10px 0,
                linear-gradient(315deg, #2c3e50 25%, transparent 25%),
                linear-gradient(45deg, #2c3e50 25%, transparent 25%);
    background-size: 20px 20px;
    opacity: 0.05;
    z-index: -1;
}

#game-result {
    font-size: 2.5rem;
    margin-bottom: 30px;
    text-shadow: 0 0 10px rgba(0, 0, 0, 0.3);
}

.stats-container {
    background-color: rgba(0, 0, 0, 0.2);
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 30px;
    border: 1px solid rgba(52, 152, 219, 0.3);
}

.stat-item {
    display: flex;
    justify-content: space-between;
    padding: 15px 0;
    border-bottom: 1px solid rgba(127, 140, 141, 0.2);
}

.stat-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.stat-label {
    font-weight: bold;
    color: #bdc3c7;
}

#final-score {
    font-size: 1.5rem;
    font-weight: bold;
    color: #e74c3c;
    text-shadow: 0 0 5px rgba(231, 76, 60, 0.3);
}

.end-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 30px;
}
